Asca Detection of Pulsed X-ray Emission from Psr J0631 1036

ASCA’s long look at the 288 ms radio pulsar PSR J0631 1036 reveals coherent X-ray pulsation from this source for the first time. The source was first detected in a serendipitous Einstein observation and later identified as a radio pulsar. Possible pulsation in the g-ray band has been detected in the Compton Gamma Ray Observatory EGRET data. The X-ray spectrum in the ASCA band is characterized by a hard power-law–type emission with a photon index of 2.3, when fitted with a single power-law function modified with absorption. An additional blackbody component of keV increases the quality of the spectral fit. The observed X-ray flux is kT 0.14 ergs s 1 cm 2 in the 1–10 keV band. We find that many characteristics of PSR J0631 1036 are 13 2.1 # 10 similar to those of middle-aged g-ray pulsars such as PSR B1055 52, PSR B0633 17 (Geminga), and PSR B0656 14. Subject headings: pulsars: general — pulsars: individual (PSR J0631 1036) — stars: neutron — X-rays: stars